The Lost Piece
by VillainousBlogger
Summary: It's been 30 years since Stan had started working on that machine. But what is its purpose? One day Dipper and Mabel, after finding Grunkle Stan's behavior more weird than usual on a certain day, they resolve to find out what had happened and how they can help. But will it be too much for them to handle? Twin-theory themed story
1. Chapter 1

It was a typical evening at the Mystery Shack. Soos and Wendy had gone home once their shifts were done, Grunkle Stan was watching TV in the living room, and the Pines' Twins were cleaning up after helping in the shack for the day. Dipper was cleaning off the dust from his clothes while Mabel was washing her hair. It was exhausting but worth it for Dipper since he could study more of the journal at night. Sometimes he could study it more on times when the shack was closed. Well, if Stan didn't saddle them with chores for the day.

"Alright," Dipper sighed, "Let's see what Grunkle Stan has in store for tomorrow." He looked at the calender on his side of the room. "Huh. The shack is gonna be...closed?"

Mabel had come out of the shower at that time. "A day off? Neat!" She exclaimed, shaking her head like a dog. "Ack! Mabel!" Dipper shouted, trying to block the water from getting on the journal. "Oops. Sorry," she grinned.

Dipper only shrugged. "It's okay Mabel. I'm just wondering why on a Saturday, where there'd be more tourists to come around than ever, Stan would keep the place closed."

"Why don't we ask?" Mabel brought up. "Never hurts to."

Dipper nodded. "You're right," he agreed, "But we'll need to be subtle about it. I'll go take a shower and then we can ask him."

One Dipper had showered and they were both in their pajamas, the two of them slowly crept downstairs and towards the living room. "Okay, I'll do the talking," Dipper whispered while Mabel held onto Waddles. They walked into the room and saw Stan was watching an old chick-flick (he apparently started getting into them) and drinking soda. It took a bit for him to notice the twins.

"Hey kids!" he grinned, "We sold a lot of junk today! Man it feels good being me!"

Dipper chuckled weakly. "Yeah, it was a good day. So what do you wanna do tomorrow?" Stan gave him a confused look. "Whatdya mean?" he asked. "W-Well it's just that the shack is closed tomorrow so I was wondering if you had plans for us. Y'know, family stuff?" Dipper couldn't read the look on his uncle's face before he took another swig of soda.

"Nah. Nothin' sappy like that. Why don't you two go into town and hang out or something." he offered. "That's so nice!" Mabel replied, giving her uncle a hug before running upstairs with Waddles trotting along behind her. Dipper glanced between where his sister and his uncle before speaking again. "Yeah, thanks Grunkle Stan," he smiled before turning to leave.

"Take care of her, alright?"

Dipper stopped to look back at his uncle who buried his face in a magazine. He was hiding something but Dipper knew he wasn't going to get anything out of him now. "I will," he replied before walking off.

Stan peeked from behind his magazine, making sure Dipper had gone upstairs before setting it down.

"Good."


	2. Chapter 2

It was a cool summer morning and the kids were shooed out of the shack early on. Stan had some work that he wanted to get done so he dropped them off at the diner for breakfast. "I'll be back around five. Don't do anything I wouldn't kids!" He gave a wink and a laugh before driving off.

The two ordered their meals from Lazy Susan and while they waited, Mabel thought out loud about some things they could do for the day while Dipper began to think about last night.

Stan specifically closed the Mystery Shack today; why? He was acting weirder than usual. Again, why? Is something important about today to Stan? If so, what? And from what he said last night, he almost seemed...depressed.

He might be able to convince Mabel to listen if they could do something to cheer their uncle up. "Hey Mabel."

Mabel stopped stacking the coffee creamers into a pyramid. "Yeah bro-bro?"

"Do you think Stan's acting weird?" he then thought about it for a second. "Well, weirder than usual?"

Mabel balanced her straw on her upper lip. "He seems like his normal weird to me. Why?"

Dipper scratched the back of his neck. "Well before I went up to bed he said something to me and seemed kinda...sad."

The straw fell as she opened her mouth. "What?! Sad?! We gotta do something to cheer him up!" The sweater-clad girl then took out a notepad and started scribbling furiously. "I say we throw him a party with all his favorite things. We'll need money, soda, older ladies-"

"I don't think it's something a party can solve," Dipper interrupted.

Mabel crossed her arms. "Party-pooper..." she mumbled.

Not too long passed before Lazy Susan brought their breakfasts to them. Chocolate chip pankcakes for Mabel and French toast for Dipper, both with sides of bacon. "Here ya go kids. Enjoy!" They both thanked her and started chowing down.

When they had finished breakfast, the duo went to see Soos. He's known Stan the longest of all of them so he might know something. They made their way to the arcade and saw him at the pinball machine with a bag of quarters and a determined look on his face. His score was pretty high but not beating the high score just yet.

"Come on...come on...!" Soos mumbled as he hit the levers and turned the knobs. The ball tossed and turned until eventually it went in the hole at the top, scoring the points he needed to win. "I did it! Whoo-hoo!"

"Yay Soos!" "Way to go man!"

The handyman turned to see his two best friends in the world cheering for him. "Hey dudes!" he greeted, giving them both hi-fives. "What brings you here?"

"We wanted to ask you something," Dipper started, "but we didn't want to interrupt your game." "You did awesome!" Mabel added. Soos grinned sheepishly. "Thanks dudes," he laughed before taking out his phone. "Can you take a pic of the score? I wanna show it to Melody when we talk tonight." Mabel agreed immediately and took several pictures of Soos next to the machine, asking him to try out different poses before handing him his phone back.

"Thanks Mabel. So whatdya wanna talk about?" Soos inquired. "Um, maybe we shouldn't discuss this here."

The trio went out back behind the arcade so they could talk privately. Dipper started the conversation. "There's something weird going on with Grunkle Stan and it has to do with today. You've know and worked with him the longest. Do you know anything?" Dipper asked. Soos blinked a few times before taking out a packet of gum and slowly unwrapped it.

"Sorry dude. I don't know much." he said before he began chewing. "It's best not to ask about this stuff, y'know?"

Dipper raised an eyebrow. "Wait, so something DID happen?" "Was it bad?" Mabel questioned.

"Dudes, I swear I don't know anything. In the ten years I've known Mr. Pines he always gets sad around this time of year and wants to be alone," he quipped, chewing loudly. Dipper pondered this for a moment. This was something big that he had to figure out. If he and Mabel could learn what happened on this day years ago, maybe it'd help Grunkle Stan.

"Soos, when do you have to meet Melody?"

Soos pondered. "Five o'clock. Why?"

Dipper gave a wry grin. "We're going to the library."


	3. Chapter 3

"So why're we at the library?" Mabel piped up as she brought over another stack of newspapers. Dipper didn't answer at first since he was organizing each pile of papers by year. The group had claimed a private room in the back for a few hours while they began their research. Once Soos had brought the last stack, he answered.

"Maybe if we look at the newspapers from the past few decades around this time of year, we might be able to figure out what could've happened." He then opened a paper. "I'll start looking from this pile. Mabel and Soos? You two start looking through those piles. If you find anything, let me know. If nothing comes up, just put it to the side so we can put it away later." Dipper glanced up at Soos. "When you have to go, it's okay. I know you wanna see Melody today."

Soos gave a small smile. "I've got time before I gotta go. But thanks dude."

Dipper smiled back and he began turning the pages with Mabel and Soos following suit.

Hours passed and the group was starting to grow weary. Mabel had begun reading the comics in the backs of the issues, laughing to keep herself from growing bored. Soos nearly fell asleep after around 20 papers. Even Dipper was starting to lose steam by this point.

"Guys...I'm not finding much. You?"

Mabel looked up from her comics. "Nope"

Soos snapped awake. "Uh-uh- Wait. Check this out." He pulled the paper off of his face and handed it to Dipper. Dipper placed it on the table and his eyes bugged out. "Whoa! Take a look at this!"

_TRAGEDY STRIKES LOCAL BUSINESS_

_Mysterious disapperance after an accident at a local tacky souvenir shop. A fire had started in the basement and while two survivors of a research team were discovered unconcious on the grounds of the Mystery Shack, one member was never found. While no evidence was found of him dying, there was no evidence of him still being on the premises._

_"I-I don't recall what happened. It's all a blur..."_

_These were the words of Fiddleford McGucket, local researcher, who was still shaken after being cared for in the hospital. Stanford Pines, owner of the Mystery Shack, was less willing to make a statement. No one knows what caused the accident or why it happened but it surely has effected these two men to their core._

Dipper sat back in his chair, hand held to his head in disbelief. Mabel gasped at the revelation and Soos was still trying to process all of this. No wonder Stan would be upset on this day. Most likely a close friend of his was taken from him along with the fire itself being traumatic. It also gave a new light on why Old Man McGucket would want to forget what had happened since he worked with whoever this person was. It could be the author.

"That's some heavy stuff..." Soos said, breaking the tension. The twins nodded in agreement, Mabel clinging close to Dipper while he patted her back. "Poor Grunkle Stan..." she muttered. Dipper frowned, feeling a whirlwind of emotions going on in his mind. Confusion at this whole new mystery, relief that they had found SOMETHING that answered most of their questions, concern about the danger that someone in their family was in, and determination in wanting to help their uncle.


	4. Chapter 4

Once the twins had said goodbye to Soos who rushed home to see Melody, they made their way back to the diner so Stan could pick them up. It was a pretty quiet wait mostly with Dipper thinking and Mabel looking through some of the books she check out. "Heehee. These Kelvin and Herbs comics are so funny!" Mabel laughed flipping through each page.

Dipper look at her oddly. "So you're not upset we spent most of the day in the library?" he asked.

"Are you kidding Dipper? I got to find collections of some of my favorite comics!" she exclaimed before giving her brother a softer look. "Besides, if we get to help Grunkle Stan, that's another bonus. And I can give him a happy sticker on my chart." She held up her little notepad with little doodles of everyone from the shack. Dipper couldn't help but smile at this. For all of Mabel's goofy behavior, she was such a good person wanting to have people be happy. Heck, Robbie and Tambry were a happy couple now because of her.

"Yeah...you're right. And thanks," Dipper replied. Mabel thwapped him on the shoulder before saying "you're welcome."

It didn't take long for Stan to pick the two up and he seemed to be in his regular spirits but Dipper could tell his eyes were red either from exhaustion since he was working all day or from crying. But he was doing a good job of hiding it.

"So," Stan started as they took the drive home, "how was your day?"

"Uh...pretty good," Dipper replied, Mabel nodding in agreement. "Yeah! We got to hang out with Soos!" Mabel piped up.

"Sounds like a good day," Stan grinned. The Pines' twins nodded quickly. Before they arrived at the diner after leaving the library, they agreed to keep what they learned a secret. If Stan was still keeping things from them, they should keep this from him for the time being. Hopefully things would be back to normal for Stan tomorrow.

After dinner, which was something Stan made but everyone agreed on ordering a pizza, they all spent some time in the living room together. Mabel read some of her new comics to Waddles who was a pretty good listener, Stan had put in a new movie and was making snarky comments as it goes on, and Dipper was pouring over the article he discovered in the library and made copies of it along with some other articles that might be useful to figuring things out.

"I'm gonna hit the john," Stan yawned as he paused the movie to get up and leave. "Save my spot okay?" When he was out of earshot, Dipper motioned for Mabel to come closer. "What'd you find bro-bro?"

"Some tabloid clippings from the Gravity Falls Gazette," Dipper replied. "I guess that's when Toby's paper was legitimate," Mabel commented. Dipper snorted. "Yeah. But there are some things that do add up. 'Mysterious Visitor Arrives in Gravity Falls'? 'Weird Lights Come From Mystery Shack In The Night'? These are clues that might help answer some of the questions we have."

Mabel picked up one of the tabloids. "I don't think there's a name or anything. How're you gonna find out anything about this guy?" Dipper gave a quick grin. "I'll tell you later. Stan's coming back." He hid the articles under today's paper while Mabel went back to playing with Waddles as Stan sat back down. There had to be a way to find out what's going on with their uncle and one way or another, they were going to find out.


	5. Chapter 5

**_Author's Note: I am aware of the epic awesomeness that was "Not What He Seems" last Monday and the revelation that came from it. I started this story before that premiered so we'll call this a different take on it. Thank you all who've kept up with it this far and I hope it'll come to a good conclusion for you._**

A few days had passed since their library adventure and Stan had hit the two kids with a bit of surprising news. "I'm gonna be out of town for a few days. Soos is gonna be watching you while I'm gone. Don't mess up the shop and take care of whatever." He gave both of them a hug before handing the keys off to Soos. With one final wave goodbye, Stan drove off, leaving Soos and the twins to open the shop and run it.

"It's so great he trusts us to take care of the shop!" Mabel grinned, polishing some of the exhibits. Dipper glanced at his sister as he swept and nodded. This would be a good opportunity to find the basement and see just what exactly is down there. For the time being though they had to work the shop and give the tours like their uncle would. At least it wasn't for a bet like last time so it should be easier to run things the usual way.

Well, maybe a bit nicer than how Stan usually treats the customers.

Mabel and Soos took turns leading tours around the shack and showing the exhibits while Dipper and Wendy ran the cash-register. Mabel put her own spins on some of the exhibits and even made up a few of her own, which seemed to impress the crowd, while Soos tried to stick with going on the usual routine.

"You okay dude?" Dipper looked up from his journal to see Wendy standing by him. "I've never seen you look so intense. What're you looking at?"

Dipper glanced up, startled from his concentration. He was so engrossed in the journal that he almost forgot Wendy was there. "Oh uh...just something from my book," he replied, laughing nervously.

Wendy gave him a knowing smile. "Well, can you take a break from that and take over for a bit? I'm gonna take my break." Dipper nodded, bookmarking his page and moving up to the stool while Wendy left for the break room. It wasn't too difficult to work the cash register since they've had to pull their weight around the Mystery Shack as long as they were staying there.

The day eventually ended with the last few stragglers leaving the shack, cheap gifts in bags and cameras filled with pictures exiting with them. It had been a long day but pretty successful without their Grunkle Stan so far. At least there wasn't a bet this time.

"Hey Dipper! We're gonna order some pizza! You want in?" Dipper looked up at his sister and Soos popping into his room, knocking him out of his concentration.

"What? Oh yeah. Sure," he replied. "But no olives!" he added.

"Got it bro-bro!" With that, the duo went downstairs and Dipper returned to his book. Maybe he was looking at this from the wrong angle. Shutting the journal for now, Dipper crept to his Grunkle Stan's bedroom. Honestly he was surprised he didn't think of this sooner but now he had the opportunity to investigate.

"Geez doesn't he ever vacuum in here?" Dipper coughed as the built up dust filled his lungs, making him gag a bit. If his uncle had something to hide, he sure picked a good way of doing it; this place was a pig sty! "If I wanted to hide something, where would I put it?" He glanced around until he saw something sticking out from under the bed?

"Ah. Here we go," he grinned. Dipper knelt down and pulled the object out, revealing to be a briefcase. Luckily it was the kind that didn't have a combination lock so he was able to get it open easily. He looked inside and found there was a rather large collection of newspaper clippings and photographs. Upon closer inspection he found there was a common theme running within the pictures; a group of three men, two of them being Grunkle Stan and a younger McGucket. Their arms were around another man, smiling with no cares in the world.

He shut the briefcase without saying anything, understanding everything now.

"Hey Dipper! Where've you been?" Mabel asked, tomato sauce on her chin.

"We saved you some pizza," Soos added. Dipper took a few slices and said thanks before eating his dinner. "You alright dude?"

Dipper looked up. "Oh yeah. I'm good you guys," he replied, giving them a smile. "Just been a long day, y'know?" The two nodded before continuing with their meals. Dipper ate as well but with more on his mind than ever.

I know what I've got to do, he thought to himself. He then glanced at his sister and friend, a twinge of guilt nagging at him. He hated to leave them out of the loop but this was something he knew he had to do alone.

He'd never forgive himself if Mabel or Soos got hurt because of him.

Meanwhile at the local dump in Gravity Falls, an old man was asleep until a revelation hit him like a ton of bricks. "Jumpin' codfish I remember! I gotta find Dipper!" He began to grab a bag and stuff it with a bunch of papers and the laptop.

"I hope I ain't too late!" McGucket mumbled as he ran out from his home.


	6. Chapter 6

It was way past midnight in Gravity Falls when Dipper snuck out of his bed, creeping downstairs to find what he was looking for. That newspaper said there was a mysterious fire in the basement of the Mystery Shack. The clues he needed had to be down there.

The question was...how would he get there?

His thoughts were interrupted when something crashed into the garbage cans outside. "Is it a raccoon?" he wondered, moving towards the door. He opened it and found something even stranger.

Old Man McGucket.

"What on earth are you doing here?" Dipper asked the shaky old man, offering a hand to help him. McGucket glanced at Dipper's confused face before grabbing him and pulling him away from the Mystery Shack. "Hey! Let me go man!"

"Shush!" McGucket whispered before looking around and dragging Dipper towards the back of the house. "I needed to talk to ya," he explained.

"Well can you make it quick? I'm a little busy." He was grateful McGucket was still enough off his rocker that he wouldn't question why a 12 year old boy would be up way past midnight.

"You got that book with ya?"

Dipper slowly took the book out. "Yeah but why-?" McGucket snatched it out of his hands and began flipping pages rapidly. "There!" Dipper looked at the page where he was pointing and his eyes nearly popped out of their sockets. It was an illustration of two people and a third person tied up and going into some sort of portal.

"I-I-I just suddenly remembered it!" McGucket explained, shaking even worse than before from fear. "A bright flash of light and a horrible laugh...I thought I forgot that awful day..." he stammered, shutting his eyes and whimpering. Dipper frowned; he hated seeing the poor guy so scared.

"McGucket," the boy started slowly, placing a hand on the older man's shoulder to calm him down. "I know you're freaked out but I need to ask you some things, okay?" McGucket slowly nodded at him. Dipper took out the newspaper article. "Do you recall anything from this day?" McGucket took the paper and scanned it before handing it back.

"Not much sorry t' say," he admitted. "But it was a very bad day...I was so scared..." McGucket began to sniffle before sitting down on the ground. "I-I lost my closest friend that day..." he hiccuped, voice hitching as he did so. Dipper didn't know what to say when McGucket looked at him with tearful eyes. "I-I-I m-miss him...even with the memories gone, I still miss him...your uncle does to..." Not really knowing what to do, Dipper slowly pulled the old man into a hug which he gratefully accepted.

"I'm so sorry you went through all of that..." Dipper said quietly, patting the man's back. "Grunkle Stan's been feeling sad about this lately to so I wanna help him."

"I wish you could, boy," McGucket whispered, wiping at his eyes. "I've wished it every day of my life..."

"But I think I can," Dipper added. McGucket pulled back and gave him a confused look before Dipper continued. "If what I've found is right and from what you remember, I might be able to help you both." He then grabbed McGucket's thin shoulders. "But I need your help, okay?" When he nodded in agreement, Dipper smiled before gaining his serious composure.

"Where is the basement entrance?"


End file.
